To the Editor.— We would like to point out an important omission in Berman's article "When the Urine is Red" (237:2753, 1977). Rifampin and its metabolites may color urine, feces, saliva, sputum, sweat, and tears a bright red-orange. This can create a great deal of anxiety for both patients and medical personnel unless they are forewarned of this "harmless" phenomenon. (Harmless is used here in a relative sense because those who have attempted to remove the stains from clothing may not consider it so.) In view of the extensive use of rifampin as an antituberculosis drug and for meningococcal meningitis prophylaxis, a mention of rifampin seems more timely than the mention of paraaminosalicylic acid, a drug used infrequently nowadays.